1. Technical Field
The present disclosure relates to remote firmware upgrade techniques, and, more particularly, to a system and method for firmware upgrade in an Advanced Metering Infrastructure (AMI).
2. Description of Related Art
With the increase in environmental awareness and energy issues, many countries are committed to build the smart grid in the hope of saving energy by having more efficient allocation and operations of power resources through monitoring and management. In order to achieve the objective, a type of infrastructure capable of two-way communication called Advanced Metering Infrastructure (AMI) has been proposed. Information about the power system can be gathered and act on through the application of AMI, which is the reason why AMI has become the backbone of the smart grid.
AMI network is regarded as the entry point for the deployment of the smart grid, and is also the infrastructure linking power supply side and demand side. The AMI network consists of three basic elements: meters, a data concentrator and a head-end server. The meters (e.g., a smart meter) and the head-end server establish communications through the intermediate data concentrator. In order to extend the useful life, scalability and real-time patching of security vulnerabilities are crucial to the meters. In other words, the meters are required to have the capability of remote firmware upgrade to accommodate for future applications or patches of security vulnerabilities. However, the number of meters in an AMI network is usually very large. In addition, the communication interfaces between the meters and the data concentrator are narrow-band networks, for example, narrow-band power line communication, so transmission is very slow and the speed of upgrade may be affected. Sometimes, the metering of the meter is affected if upgrade is not completed. For example, firmware upgrade in the current AMI is one-to-one, i.e., the head-end server providing a firmware image file to the data concentrator, which then partitions the firmware image file into a plurality of small files and transmits them to each meter. When the file(s) missing in each meter is different, the data concentrator has to retransmit those missing files individually. This is time consuming and inefficient. Thus, it is a major challenge to accomplish firmware upgrade of the meters without affecting metering.
In addition to the efficiency of firmware upgrade, security protection is also an important factor to the success of the firmware upgrade. During a firmware upgrade, one needs to avoid an attacker using a backdoor firmware to steal confidential information on the AMI network or violate users' privacy. In particular, the data concentrator needs to ensure that the source of the received firmware image file is trusted and the meters need to verify the validity of the files coming from the data concentrator in order to establish a complete security protection. It is clear from the foregoing that the procedure of meter firmware upgrade in the existing AMI still needs to be improved. For example, firmware upgrade could be completed in one metering cycle (about 15 minutes), and security measures such as source verification and end-to-end security protection could be provided. The legitimacy of the firmware source could be ensured before meter firmware upgrade is performed to avoid compromise of the procedure due to the data concentrator being compromised.
Therefore, there is a need for a method that is capable of remotely upgrading firmware in the meters of an AMI with increased efficiency while ensuring the security of the firmware upgrade without the need to change the existing architecture of the AMI network.